Sending Out An Sos

Wireless Gadgets Are Everywhere, And So Is Potential For Interference

January 26, 2000|By Jon Van, Tribune Staff Writer.

A giant construction crane that moves unbidden, a nuclear power unit that shuts down for no apparent reason and distress signals from a phantom boat are workaday stuff to Brian Mattson and his colleagues.

But the Wheeling firm that Mattson manages isn't a local branch of Ghostbusters, even though it often focuses on the spookier side of technology.

Errant radio signals, not forces from the spirit world, are what sometimes make electronic control equipment seem to develop a mind of its own. And as wireless phones, pagers and other gadgets proliferate, the problem grows more complex each year.

It took only a walkie-talkie transmission to trigger a safety mechanism that shut down a nuclear power plant unit, for example. And the Coast Guard once launched a search-and-rescue mission when radio emissions from a computer screen were interpreted as a boater's SOS.

As new technology is introduced in coming months that enables electronic devices to communicate with each other without wires, the potential for trouble can only expand.

The problem stems from the fact that transistors--the basic workhorses of electronics--can act as tiny radios, sending and receiving weak signals. As more transistors are packed together on computer chips, they are designed to run at lower voltages and higher speeds. That reduces heat emissions and boosts performance, but it also makes them more susceptible to errant radio signals that can cause malfunctions.

Even as the potential for trouble increases, universities are putting less emphasis on electromagnetic interference than they once did, so young electrical engineers tend to have little or no understanding of how vulnerable modern equipment can be.

It all adds up to more work for DLS Electronic Systems Inc., a Wheeling-based specialist in electromagnetic troubleshooting.

Yet the work isn't always welcome, said Mattson, general manager of the firm, which tests equipment and consults with customers.

"A lot of times customers will come to us after they'd designed and built a new product and then find there's a problem," Mattson said. "Going back into the process to eliminate the problem can be costly and time-consuming.

"It's often the case where if they'd only thought about this when they first designed their product, it would have been relatively easy to avoid the problem in the first place."

To address the problem, DLS and the University of Wisconsin cooperate to regularly offer engineering courses on electromagnetic compatibility design, including one now concluding in Northbrook. .

Despite this outreach, the firm's lab equipment regularly uncovers devices that either generate errant radio frequency interference or are themselves susceptible to such interference.

One example is a portable electric power source intended for use in recreational vehicles. The product emitted electromagnetic signals strong enough to interfere with radio and TV reception, which are among the more popular appliances in modern campers.

"They had to recall a lot of products and do a redesign," Mattson said.

Electromagnetic interference is, of course, a phenomenon of modern technology's escalating complexities. It was first noticed by the military in the late 1940s when the strong signals emitted by radar apparatus caused radio equipment to malfunction.

It wasn't until the 1980s that the Federal Communications Commission adopted regulations to address the problems.

"Cordless phones and garage door openers were two of the first items where people started to see interference," Mattson said.

Even though the FCC and regulatory bodies in the European Union have numerous regulations governing appliances and the type of signals they may emit, private companies do the bulk of work to control such emissions.

Often such standards amount to "gentlemen's agreements" subscribed to by industry because it's in everybody's interest that their equipment won't malfunction, said Siemens Corp. engineer Stephen Berger, chairman of one standards committee and a member of another.

There are about 5,000 engineers worldwide who belong to the Electromagnetic Compatibility Society of the Institute of Electrical and Electronic Engineers, the leading international professional organization in this realm.

"Sometimes we develop a standard because there's a noticeable problem," said Berger, "but we prefer to get to work before things get to that point."

There are probably 30 projects going right now where engineers are developing standards intended to prevent future trouble, he said.

Four different standards to govern wireless local area computer networks are currently competing for favor, for instance.

Providing compatibility between wireless phones and hearing aids so that people with hearing disabilities will be able to use cell phones is another example of this work.

"We're funding five studies to support writing the hearing-aid standard," said Berger, "and there've been about 100 engineers involved."